1. Field of the Invention
The invention relates to a padlock with a U-shaped lock casing, more particularly to a padlock which can minimize malfunctioning thereof due to spring fatigue.
2. Description of the Related Art
A conventional padlock includes a lock casing, a key-operated lock core unit mounted in the lock casing, a shackle bar inserted between opposite shackle mounting portions of the lock casing for retaining an object on the lock casing between the opposite shackle mounting portions, and spring-loaded tumbler means associated operably with the lock core unit for engaging removably the shackle bar. The conventional padlock generally suffers from the disadvantage that the lock core unit is not removable from the lock casing. As such, in case of spring fatigue that leads to malfunctioning of the padlock, the entire padlock has to be discarded although the lock core unit is still operable. In Applicant""s co-pending U.S. patent application Ser. No. 09/395,521, filed on Sep. 14, 1999, the entire disclosure of which is incorporated herein by reference, there is disclosed a padlock assembly with a lock casing and a lock mechanism which is mounted removably in the lock casing. A spring-loaded latch bar is provided in the lock casing, and is associated operably with the lock mechanism for engaging removably a shackle bar of the padlock assembly. As spring fatigue of the latch bar is usually unavoidable after the padlock assembly has been in use for a period of time, it is thus desirable to provide a padlock which incorporates a fewer number of spring members to reduce the possibility of malfunctioning thereof due to spring fatigue.
Therefore, the object of the present invention is to provide a padlock which can minimize malfunctioning thereof due to spring fatigue.
Accordingly, the padlock of the present invention includes a lock casing, a key-operated lock core unit, a shackle bar, and a catch member. The lock casing has first and second end surfaces which are opposite to each other in a longitudinal direction, and includes a lock core mounting portion adjacent to the first end surface and formed with a core receiving space that extends in the longitudinal direction from the first end surface toward the second end surface, a latch receiving portion adjacent to the second end surface and formed with a latch recess communicated with the core receiving space, a first shackle mounting portion that extends from the lock core mounting portion in a first transverse direction transverse to the longitudinal direction and that is formed with a first shackle insert hole, and a second shackle mounting portion that extends from the latch receiving portion in the first transverse direction and that is opposite to the first shackle mounting portion. The second shackle mounting portion is formed with a second shackle insert hole that is aligned with the first shackle insert hole in the longitudinal direction. The second shackle mounting portion is further formed with a slide channel that extends in the first transverse direction to communicate the second shackle insert hole with the latch recess. The lock core unit includes a cylindrical lock core and a latch member. The lock core is formed with a keyhole, and is disposed in the core receiving space. The lock core is adapted to be rotated inside the core receiving space upon insertion of a corresponding key into the keyhole. The lock core has one end disposed adjacent to the latch recess. The latch member is connected to said one end of the lock core, and extends into the latch recess. The latch member is rotatable inside the latch recess between locking and unlocking positions when the corresponding key is operated. The shackle bar has a first end extending into the first shackle insert hole, and a second end extending into the second shackle insert hole. At least one of the first and second ends is removable from a corresponding one of the first and second shackle insert holes. The catch member is disposed slidably in the latch recess, and has a first abutment wall which is formed with a shackle engaging projection that extends into the slide channel, a second abutment wall spaced apart from the first abutment wall in the first transverse direction, and a latch cavity defined between the first and second abutment walls for extension of the latch member thereinto. The latch member pushes the first abutment wall of the catch member for moving the catch member in the first transverse direction toward the second shackle mounting portion so as to enable the shackle engaging projection to project into the second shackle insert hole for engaging the shackle bar when the latch member is disposed in the locking position. The latch member pushes the second abutment wall of the catch member for moving the catch member in a direction opposite to the first transverse direction away from the second shackle mounting portion so as to enable the shackle engaging portion to retract into the slide channel for disengaging from the shackle bar when the latch member is disposed in the unlocking position.